ABSTRACT
Introduction: The objective of this study was to characterize the experiences and overall satisfaction of patients and providers with the March 2020 transition to telehealth in a psychiatric setting (telepsychiatry). The study also investigated how socio-demographic and clinical characteristics impact an individual's experiences and satisfaction with telepsychiatry. Methods: Responses were collected from 604 patients and 154 providers engaged in clinical care at one of three participating Johns Hopkins Medicine outpatient psychiatric clinics between January 2020-March 2021. Survey data were collected by self-report via Qualtrics or telephone follow-up. Results: Respondents were predominately female and White. Over 70% of patients and providers were generally satisfied with telepsychiatry. However, providers were more likely to favor in-person care over telepsychiatry for post-pandemic care 48% to 17% respectively, while 35% rated both modalities equivalently. Patients were more evenly divided with 45% preferring telepsychiatry compared to 42% for in-person care, and only 13% rating them equivalently. Among providers, technical difficulties were significantly associated with both less satisfaction and lower preference for telepsychiatry [odds ratio for satisfaction (ORS) = 0.12; odds ratio for preference (ORP) = 0.13]. For patients, factors significantly associated with both lower satisfaction and lower preference for telepsychiatry included technical difficulties (ORS = 0.20; ORP = 0.41), unstable access to the internet (ORS = 0.46; ORP = 0.50), worsening depression (ORS = 0.38; ORP = 0.36), and worsening anxiety (ORS = 0.41; ORP = 0.40). Factors associated with greater satisfaction and higher preference for telepsychiatry among patients included higher education (ORS = 2.13; ORP = 1.96) and a decrease in technical difficulties over time (ORS = 2.86; ORP = 2.35). Discussion: Patients and providers were satisfied with telepsychiatry. However, there were greater differences between them in preferences for continuing to use telepsychiatry post-pandemic. These findings highlight factors that influence patient and provider preferences and should be addressed to optimize the use of telepsychiatry in the future.
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BACKGROUND: Behavioral and emotional dyscontrol commonly occur following traumatic brain injury (TBI). Neuroimaging and electrophysiological correlates of dyscontrol have not been systematically summarized in the literature to date. OBJECTIVE: To complete a systematic review of the literature examining neuroimaging and electrophysiological findings related to behavioral and emotional dyscontrol due to TBI. METHODS: A Preferred Reporting Items for Systematic Reviews and Meta-Analyses-compliant literature search was conducted in PubMed (MEDLINE), PsycINFO, EMBASE, and Scopus databases prior to May 2019. The database query yielded 4392 unique articles. These articles were narrowed based on specific inclusion criteria (e.g., clear TBI definition, statistical analysis of the relationship between neuroimaging and dyscontrol). RESULTS: A final cohort of 24 articles resulted, comprising findings from 1552 patients with TBI. Studies included civilian (n = 12), military (n = 10), and sport (n = 2) samples with significant variation in the severity of TBI incorporated. Global and region-based structural imaging was more frequently used to study dyscontrol than functional imaging or diffusion tensor imaging. The prefrontal cortex was the most common neuroanatomical region associated with behavioral and emotional dyscontrol, followed by other frontal and temporal lobe findings. CONCLUSIONS: Frontal and temporal lesions are most strongly implicated in the development of postinjury dyscontrol symptoms although they are also the most frequently investigated regions of the brain for these symptom categories. Future studies can make valuable contributions to the field by (1) emphasizing consistent definitions of behavioral and emotional dyscontrol, (2) assessing premorbid dyscontrol symptoms in subjects, (3) utilizing functional or structural connectivity-based imaging techniques, or (4) restricting analyses to more focused brain regions.
Subject(s)
Brain Injuries, Traumatic , Brain Injuries , Humans , Diffusion Tensor Imaging , Brain Injuries, Traumatic/diagnostic imaging , Neuroimaging , Emotions , Brain Injuries/pathologyABSTRACT
INTRODUCTION: Text messaging interventions (TMI) are promising for addressing heavy episodic drinking (HED) in non-treatment-seeking postpartum women. Their anonymous delivery can overcome fear of consequences that often prevents postpartum women from seeking treatment for HED. We assessed feasibility and acceptability of text messaging to inform the development of a tailored TMI for postpartum HED. METHODS: We surveyed 165 postpartum women recruited via a national Qualtrics panel on their drinking behaviours, mobile technology use and TMI preferences. RESULTS: Twenty-five percent of the sample (N = 41) were classified as heavy episodic drinkers, with significant drinking reported before, during and after pregnancy, supporting the need for intervention. Feasibility of text messaging was supported by nearly universal mobile phone ownership and text messaging. Attitudes and intervention preferences varied, with 30% of HEDs likely to participate in an intervention asking them to receive automated messages, and 46% likely to participate in an intervention that included live texting with a counsellor. Respondents were more likely to participate in a study that asked them to respond to messages about mood and stress (63%) than daily drinking behaviours (35%), and were most interested in a TMI that included live texting with a counsellor. Nearly half the sample endorsed fear of child removal as a significant barrier to participation. DISCUSSION AND CONCLUSIONS: Findings support the feasibility of text messaging as an intervention approach for postpartum HEDs. Postpartum women may have unique concerns and preferences that differ from other groups of HEDs, making a user-centred design approach critical.
Subject(s)
Alcoholic Intoxication , Cell Phone , Text Messaging , Female , Humans , Postpartum Period , Pregnancy , Surveys and QuestionnairesABSTRACT
PURPOSE: A substantial fraction of all non-small cell lung cancers(NSCLC) carry a mutation in the EGFR gene for which an effective treatment with anti-tyrosine kinases(TKIs) is available. We studied the long term survival of these patients following the introduction of TKIs. EXPERIMENTAL DESIGN: All consecutive cases of NSCLC newly diagnosed with advanced disease were referred for free tumor EGFR mutation testing at Clalit's national personalized medicine laboratory. Mutations and deletions in target codons 18-21 of EGFR were sought using RT-PCR and fragment analysis. Comprehensive EMRs were used to collect full data on treatments and clinical status. RESULTS: A cohort of 3,062 advanced NSCLC cases, included 481(15.7%) somatic EGFR mutation carriers (17.5% of all adenocarcinomas, 26.7% of females with adenocarcinomas). TKIs treatment to EGFR mutation carriers was provided to 85% of all eligible. After a median follow up period of 15.9 months for EGFR mutated cases the hazard ratio for overall survival of EGFR-mutated NSCLC treated with TKIs was 0.55(0.49-0.63, p<0.0001) when compared with EGFR wild-type(WT) tumors under usual care. After adjusting for age, sex, ethnicity, smoking history and tumor histology, all of which had an independently significant effect on survival, the HR for TKI-treated, EGFR-mutated tumors, was 0.63 (0.55-0.71, p<0.0001). Treating EGFR-WT cases with TKIs yielded a high HR=1.32 (1.19-1.48). CONCLUSIONS: TKIs given to EGFR mutated advanced NSCLC demonstrated a substantial survival benefit for at least five years. Squamous histology, smoking, male sex and Arab ethnicity were associated with higher NSCLC mortality hazard. Treating non-EGFR-mutated NSCLC with TKIs seems detrimental. Statement of Significance: ⢠TKIs given to EGFR mutated advanced NSCLC demonstrated a substantial survival benefit for at least five years but not much longer. ⢠Treating non-EGFR-mutated NSCLC with TKIs seems detrimental and should probably be avoided. ⢠Squamous histology of non-small cell lung cancer, smoking history, male sex and Arab ethnicity were associated with altogether higher NSCLC mortality hazard.
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BACKGROUND: Most patients with non-small cell lung cancer (NSCLC) present with advanced disease and have poor long-term prognosis. Advanced NSCLC that contains characteristic mutations in epidermal growth factor receptor (EGFR) are highly sensitive to EGFR tyrosine kinase inhibitors (TKIs). EGFR exon 19 insertions mutations are rare, and response to TKIs is still unclear. CASE DESCRIPTION: A young Arab patient was diagnosed with metastatic disease of NSCLC harboring an exon 19 insertion of 18 nucleotides. The patient showed a very impressive clinical and radiological response within few weeks treatment with TKI agent. DISCUSSION AND EVALUATION: To our best knowledge, This case is the first case in Arab woman and one of few cases described in the literature with this rare mutation responding to TKIs. CONCLUSIONS: Treatment with TKIs should be the standard choice in patients with metastatic disease NSCLC.
ABSTRACT
Many viruses deliver their genomes into the nucleoplasm for viral transcription and replication. Here, we describe a novel cell-free system to elucidate specific interactions between viruses and nuclear pore complexes (NPCs). Nuclei reconstituted in vitro from egg extracts of Xenopus laevis, an established biochemical system to decipher nuclear functions, were incubated with GFP-tagged capsids of herpes simplex virus, an alphaherpesvirus replicating in the nucleus. Capsid binding to NPCs was analyzed using fluorescence and field emission scanning electron microscopy. Tegument-free capsids or viral capsids exposing inner tegument proteins on their surface bound to nuclei, while capsids inactivated by a high-salt treatment or covered by inner and outer tegument showed less binding. There was little binding of the four different capsid types to nuclei lacking functional NPCs. This novel approach provides a powerful system to elucidate the molecular mechanisms that enable viral structures to engage with NPCs. Furthermore, this assay could be expanded to identify molecular cues triggering viral genome uncoating and nuclear import of viral genomes.
Subject(s)
Capsid/metabolism , Nuclear Pore/metabolism , Active Transport, Cell Nucleus , Animals , Capsid/ultrastructure , Capsid Proteins/metabolism , Cell-Free System , Herpesvirus 1, Human/metabolism , Nuclear Pore/virology , Protein Binding , XenopusABSTRACT
Animal models are important tools for studies of human disease, but developing these models is a particular challenge with regard to organisms with restricted host ranges, such as the human stomach pathogen Helicobacter pylori. In most cases, H. pylori infects the stomach for many decades before symptoms appear, distinguishing it from many bacterial pathogens that cause acute infection. To model chronic infection in the mouse, a human clinical isolate was selected for its ability to survive for 2 months in the mouse stomach, and the resulting strain, MSD132, colonized the mouse stomach for at least 28 weeks. During selection, the cagY component of the Cag type IV secretion system was mutated, disrupting a key interaction with host cells. Increases in both bacterial persistence and bacterial burden occurred prior to this mutation, and a mixed population of cagY(+) and cagY mutant cells was isolated from a single mouse, suggesting that mutations accumulate during selection and that factors in addition to the Cag apparatus are important for murine adaptation. Diversity in both alleles and genes is common in H. pylori strains, and natural competence mediates a high rate of interstrain genetic exchange. Mutations of the Com apparatus, a membrane DNA transporter, and DprA, a cytosolic competence factor, resulted in reduced persistence, although initial colonization was normal. Thus, exchange of DNA between genetically heterogeneous H. pylori strains may improve chronic colonization. The strains and methods described here will be important tools for defining both the spectrum of mutations that promote murine adaptation and the genetic program of chronic infection.
Subject(s)
Helicobacter Infections/microbiology , Helicobacter pylori/genetics , Alleles , Animals , Bacterial Proteins/genetics , Chronic Disease , Disease Models, Animal , Female , Helicobacter Infections/genetics , Humans , Mice , Mice, Inbred C57BL , Mutation , Stomach/microbiologyABSTRACT
MUTYH is associated with colorectal cancer (CRC) risk. We studied the frequency of MUTYH and risk of CRC in Arabs, North African and European Jews. Participants were all 593 Sephardi Moroccan Jews (232 cases, 361 controls) and all 631 Arabs (327 cases, 304 controls) recruited into a population-based study of colorectal cancer in Israel, as well as a random sample of 189 Ashkenazi Jewish cases. Two MUTYH mutations, G396D and Y179C, were studied in 1,413 individuals, with MUTYH sequence analysis in 46 cases with CRC in a sibling or adenoma. No carriers of mutations in MUTYH were identified in Ashkenazi Jews and only one in Arabs. In Sephardi Jews, 28 carriers of G396D, 25 (4.2%) heterozygotes and 3 (0.5%) homozygotes were identified. Four (0.7%) were heterozygote carriers of the Y179C mutation. Two compound heterozygous carriers of Y179C and G396D were identified. Homozygote carriers of G396D had nonsignificantly elevated risk of CRC (OR = 11.0, 95% CI: 0.91-213.9, p = 0.06), and combined bi-allelic carriers of G396D and Y179C had increased risk, OR = 17.4, 95% CI = (1.9-316.7, p = 0.009). Four of five bi-allelic carriers reported a family history of CRC. Sequencing of 46 colorectal cancer cases with family history and additional adenomas, did not identify any other non-founder mutations. MUTYH carriers of the two common founder mutations are profoundly under-represented among both Ashkenazi Jews and Arabs. The prevalence of MUTYH carriers of the common mutations is much higher in Sephardi Jews. Bi-allelic carriers of mutations in MUTYH, are associated with highly risk of colorectal cancer.
Subject(s)
Colorectal Neoplasms/genetics , DNA Glycosylases/genetics , Genetic Predisposition to Disease , Mutation , Adenoma/ethnology , Adenoma/genetics , Aged , Aged, 80 and over , Arabs/genetics , Base Sequence , Case-Control Studies , Colorectal Neoplasms/ethnology , Female , Founder Effect , Heterozygote , Humans , Israel , Jews/genetics , Male , Middle Aged , Molecular Sequence DataABSTRACT
Lipopolysaccharide (LPS) structural modifications have been shown to specifically affect the pathogenesis of many gram-negative pathogens. In Francisella, modification of the lipid A component of LPS resulted in a molecule with no to low endotoxic activity. The role of the terminal lipid A phosphates in host recognition and pathogenesis was determined using a Francisella novicida mutant that lacked the 4' phosphatase enzyme (LpxF). The lipid A of this strain retained the phosphate moiety at the 4' position and the N-linked fatty acid at the 3' position on the diglucosamine backbone. Studies were undertaken to determine the pathogenesis of this mutant strain via the pulmonary and subcutaneous routes of infection. Mice infected with the lpxF-null F. novicida mutant by either route survived primary infection and subsequently developed protective immunity against a lethal wild-type (WT) F. novicida challenge. To determine the mechanism(s) by which the host controlled primary infection by the lpxF-null mutant, the role of innate immune components, including Toll-like receptor 2 (TLR2), TLR4, caspase-1, MyD88, alpha interferon (IFN-α), and gamma interferon(IFN-γ), was examined using knockout mice. Interestingly, only the IFN-γ knockout mice succumbed to a primary lpxF-null F. novicida mutant infection, highlighting the importance of IFN-γ production. To determine the role of components of the host adaptive immune system that elicit the long-term protective immune response, T- and B-cell deficient RAG1(-/-) mice were examined. All mice survived primary infection; however, RAG1(-/-) mice did not survive WT challenge, highlighting a role for T and B cells in the protective immune response.
Subject(s)
Francisella/immunology , Francisella/pathogenicity , Lipid A/metabolism , Lipid A/toxicity , Phosphates/metabolism , Animals , Cytokines/genetics , Disease Models, Animal , Female , Francisella/metabolism , Gene Knockout Techniques , Gram-Negative Bacterial Infections/immunology , Gram-Negative Bacterial Infections/microbiology , Gram-Negative Bacterial Infections/mortality , Gram-Negative Bacterial Infections/pathology , Immunity, Innate , Lipid A/immunology , Mice , Mice, Inbred C57BL , Mice, Knockout , Phosphoric Monoester Hydrolases/genetics , Phosphoric Monoester Hydrolases/metabolism , Receptors, Immunologic/genetics , Survival Analysis , VirulenceABSTRACT
BACKGROUND: Variants of the mutY homolog gene MutYH, a DNA repair gene, are associated with increased risk of colorectal cancer; however, it remains unclear whether these variants also are associated with the risk of other cancers. The authors studied the risk of breast cancer associated with MutYH variants in a unique ethnic group of Sephardi Jews in Israel with a high prevalence of MutYH mutations. METHODS: The study participants were 930 Sephardi Jewish women of North African origin who were recruited into the population-based case-control Breast Cancer in Northern Israel Study (BCINIS) either as breast cancer cases or as healthy controls. All participants contributed a blood sample and completed an interview. Two MutYH variants, a glycine-to-aspartic acid substitution at codon 396 (G396D) and a tyrosine-to-cysteine substitution at codon 179 (Y179C), were studied. RESULTS: In the Sephardi Jews, among the healthy controls, 20 women (3.7%) were homozygote or heterozygote carriers of the G396D variant, and 4 women (0.7%) were heterozygote carriers of the Y179C variant. Breast cancer cases had a 6.7% prevalence of G396D, yielding a significantly elevated risk estimate for breast cancer (odds ratio, 1.86; 95% confidence interval, 1.02-3.39; P = .039). The tumors detected in carriers with MutYH variants were similar in characteristics to those without MutYH variants, as was the age at diagnosis. CONCLUSIONS: Carriers of variants in MutYH, although not very common, may have an increased risk of breast cancer in Jews of North African origin. Identification of such carriers and special surveillance protocols may be warranted.
Subject(s)
DNA Glycosylases/genetics , Jews/genetics , Africa, Northern/ethnology , Aged , Breast Neoplasms/genetics , Case-Control Studies , Female , Genetic Predisposition to Disease , Heterozygote , Humans , Israel , Middle Aged , MutationABSTRACT
Nuclear pore complexes (NPCs) are formed during two separate stages of the metazoan cell cycle. They are assembled into the re-forming nuclear envelope (NE) at the exit from mitosis and into an intact, expanding NE during interphase. Here, we show that a soluble internal fragment of the membrane nucleoporin POM121 has a dominant-negative effect on both modes of assembly in a cell-free reconstitution system. The soluble POM121 fragment binds chromatin at sites that are distinct from ELYS-Nup107-160 'seeding' sites and prevents membrane enclosure and NPC formation. Importin-ß negatively regulates chromatin binding by the POM121 fragment through a conserved NLS motif and is also shown to affect the recruitment of the endogenous membrane protein to chromatin in the full assembly system. When an intact NE is present before the addition of the dominant-negative fragment, NPCs are inserted into the NE but membrane expansion is inhibited. This results in densely packed NPCs with no intervening membrane patches, as visualized by scanning electron microscopy. We conclude that POM121 plays an important role in both modes of assembly and links nuclear membrane formation and expansion to nuclear pore biogenesis.
Subject(s)
Chromatin/metabolism , Nuclear Pore Complex Proteins/genetics , Nuclear Pore Complex Proteins/metabolism , Nuclear Pore/metabolism , Xenopus Proteins/genetics , Xenopus Proteins/metabolism , Xenopus/metabolism , Animals , Mutation , Nuclear Envelope/genetics , Nuclear Envelope/metabolism , Nuclear Pore/genetics , Protein Binding , Xenopus/geneticsABSTRACT
The 26S proteasome is a conserved 2.5 MDa protein degradation machine that localizes to different cellular compartments, including the nucleus. Little is known about the specific targeting mechanisms of proteasomes in eukaryotic cells. We used a cell-free nuclear reconstitution system to test for nuclear targeting and import of distinct proteasome species. Three types of stable, proteolytically active proteasomes particles were purified from Xenopus egg cytosol. Two of these, the 26S holoenzyme and the 20S core particle, were targeted to the nuclear periphery but did not reach the nucleoplasm. This targeting depends on the presence of mature nuclear pore complexes (NPCs) in the nuclear envelope. A third, novel form, designated here as 20S+, was actively imported through NPCs. The 20S+ proteasome particle resembles recently described structural intermediates from other systems. Nuclear import of this particle requires functional NPCs, but it is not directly regulated by the Ran GTPase cycle. The mere presence of the associated "+" factors is sufficient to reconstitute nuclear targeting and confer onto isolated 20S core particles the ability to be imported. Stable 20S+ particles found in unfertilized eggs may provide a means for quick mobilization of existing proteasome particles into newly formed nuclear compartments during early development.
Subject(s)
Active Transport, Cell Nucleus/physiology , Proteasome Endopeptidase Complex/metabolism , Animals , Cytoplasm/metabolism , Nuclear Envelope/metabolism , Nuclear Envelope/ultrastructure , Nuclear Pore/metabolism , Nuclear Pore/ultrastructure , Oocytes/cytology , Oocytes/metabolism , Proteasome Endopeptidase Complex/genetics , Proteasome Endopeptidase Complex/isolation & purification , Protein Subunits/genetics , Protein Subunits/metabolism , Recombinant Proteins/genetics , Recombinant Proteins/metabolism , Xenopus laevis/metabolism , ran GTP-Binding Protein/metabolismABSTRACT
BACKGROUND: Metastatic colorectal cancer is frequently treated with irinotecan, a topoisomerase-I inhibitor. The UGT1A1 gene encodes for an enzyme that metabolizes irinotecan, and its genetic variants were shown to be associated with increased drug toxicity. We evaluated clinical outcomes associated with the UGT1A1*28 variant. METHODS: The study included 329 colorectal cancer patients from the Israeli population-based Molecular Epidemiology of Colorectal Cancer study who were treated with a chemotherapy regimen that included irinotecan. Patients with metastases or disease recurrence were followed up for a median period of 2 years after occurrence of the event. Study end points were appearance of grade 3-4 hematological and gastroenterological toxicity, hospitalization due to toxic events (mostly neutropenia, fever, diarrhea, or vomiting), length of hospitalization, and overall survival. UGT1A1*28 was genotyped from peripheral blood DNA by fragment analysis and reported as number of TATA sequence repeats in the promoter of the gene. RESULTS: The 7/7 variant of UGT1A1*28 was detected in 11.9% of the 329 participants. Grade 3-4 hematological toxicity was significantly higher in 7/7 carriers compared with 6/7 and 6/6 carriers (48.0%,10.2%, and 7.7% respectively; P < .001), as was the risk of toxicity-related hospitalization (45.8%, 25.3%, and 14.4% respectively; P = .001). Both short-term death within 2 months of treatment start (12.8%, 5.2%, and 2.9%, respectively) and median overall survival (1.6, 2.0, and 2.4 years, respectively; P = .01) were significantly worse in the 7/7 carriers. The age/stage-adjusted hazard ratio for patients with the 7/7 genotype compared with 6/6 was 1.7 (95% confidence interval, 1.1-2.3). CONCLUSIONS: The UGT1A1*28 7/7 genotype is strongly associated with severe hematological toxicity and higher hospitalization rate and predicts lower survival of colorectal cancer in users of irinotecan.
Subject(s)
Antineoplastic Agents, Phytogenic/adverse effects , Camptothecin/analogs & derivatives , Colorectal Neoplasms/drug therapy , Colorectal Neoplasms/genetics , Glucuronosyltransferase/genetics , Polymorphism, Genetic , Adult , Aged , Camptothecin/adverse effects , Colorectal Neoplasms/mortality , Female , Genotype , Humans , Irinotecan , Leukopenia/chemically induced , Leukopenia/genetics , Male , Middle Aged , Neutropenia/chemically induced , Neutropenia/geneticsABSTRACT
We report on comprehensive structure characterization of lipid A extracted from Yersinia pestis (Yp) for determination of its phosphorylation configuration that was achieved by combining the methods of molecular biology with high-resolution tandem mass spectrometry. The phosphorylation pattern of diphosphorylated lipid A extracted from Yp has recently been found to be a heterogeneous mixture of C-1 and C-4' bisphosphate, C-1 pyrophosphate, and C-4' pyrophosphate (Proc. Natl. Acad. Sci. 2008, 105, 12742). To reduce the inherent phosphate heterogeneity of diphosphorylated lipid A extracted from Yp, we incorporated specific C-1 and C-4' position phosphatases into wild type KIM6+ Yp grown at 37 degrees C. Comprehensive high-resolution tandem mass spectrometric analyses of lipid A extracted from Yp modified with either the C-1 or C-4' phosphatase allowed for unambiguous structure assignment of monophosphorylated and diphosphorylated lipid A and distinction of isomeric bisphosphate and pyrophosphate forms. The prevalent aminoarabinose modification was determined to be exclusively attached to the lipid A disaccharide via a phospho-diester linkage at either or both the C-1 and C-4' positions.
Subject(s)
Lipid A/chemistry , Phosphates/chemistry , Tandem Mass Spectrometry/methods , Yersinia pestis/chemistry , Diphosphates/chemistry , Lipid A/isolation & purification , Models, Molecular , Molecular Conformation , PhosphorylationABSTRACT
A novel sensitive liquid chromatography/mass spectrometry-based assay was developed for the quantitation of aminosugars, including 2-amino-2-deoxyglucose (glucosamine, GlcN), 2-amino-2-deoxygalactose (galactosamine, GalN), and 4-amino-4-deoxyarabinose (aminoarabinose, AraN), and for ethanolamine (EtN), present in lipid A. This assay enables the identification and quantitation of all amino-containing moieties present in lipopolysaccharide or lipid A from a single sample. The method was applied to the analysis of lipid A (endotoxin) isolated from a variety of biosynthetic and regulatory mutants of Salmonella enterica serovar Typhimurium and Francisella tularensis subspecies novicida. Lipid A is treated with trifluoroacetic acid to liberate and deacetylate individual aminosugars and mass tagged with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate, which reacts with primary and secondary amines. The derivatives are separated using reversed-phase chromatography and analyzed using a single quadrupole mass spectrometer to detect quantities as small as 20 fmol. GalN was detected only in Francisella and AraN only in Salmonella, while GlcN was detected in lipid A samples from both species of bacteria. Additionally, we found an approximately 10-fold increase in the level of AraN in lipid A isolated from Salmonella grown in magnesium-limited versus magnesium-replete conditions. Salmonella with defined mutations in lipid A synthesis and regulatory genes were used to further validate the assay. Salmonella with null mutations in the phoP, pmrE, and prmF genes were unable to add AraN to their lipid A, while Salmonella with constitutively active phoP and pmrA exhibited AraN modification of lipid A even in the normally repressive magnesium-replete growth condition. The described assay produces excellent repeatability and reproducibility for the detection of amino-containing moieties in lipid A from a variety of bacterial sources.
Subject(s)
Amino Sugars/analysis , Francisella tularensis/chemistry , Lipid A/chemistry , Salmonella typhi/chemistry , Arabinose/analogs & derivatives , Arabinose/analysis , Chromatography, Liquid/methods , Ethanolamine/analysis , Francisella tularensis/genetics , Francisella tularensis/metabolism , Galactosamine/analysis , Glucosamine/analysis , Linear Models , Mass Spectrometry/methods , Models, Chemical , Mutation , Reproducibility of Results , Salmonella typhi/genetics , Salmonella typhi/metabolism , Sensitivity and SpecificityABSTRACT
We describe a novel, potent peptide substrate mimetic inhibitor of protein kinase B (PKB/Akt). The compound selectively kills prostate cancer cells, in which PKB is highly activated, but not normal cells, or cancer cells in which PKB is not activated. The inhibitor induces apoptosis and inhibits the phosphorylation of PKB substrates in prostate cancer cell lines and significantly increases the efficacy of chemotherapy agents to induce prostate cancer cell death, when given in combination. In vivo, the inhibitor exhibits a strong antitumor effect in two prostate cancer mouse models. Moreover, treated animals develop significantly less lung metastases compared to untreated ones, and the effect is accompanied by a significant decrease in blood PSA [prostate-specific antigen] levels in treated animals. This compound and its potential analogues may be developed into novel, potent, and safe anticancer agents, both as stand-alone treatment and in combination with other chemotherapy agents.
Subject(s)
Cholesterol Esters/therapeutic use , Enzyme Inhibitors/therapeutic use , Oligopeptides/therapeutic use , Prostatic Neoplasms/drug therapy , Proto-Oncogene Proteins c-akt/antagonists & inhibitors , Animals , Apoptosis/drug effects , Cell Line , Cell Line, Tumor , Cell Proliferation/drug effects , Humans , Male , Mice , Mitoxantrone/pharmacology , Models, Molecular , Prostate-Specific Antigen/blood , Signal Transduction/drug effectsABSTRACT
Embryonic stem (ES) cells are cells derived from the inner cell mass of a blastocyst stage embryo. These self-renewing multipotent cells are able to differentiate to the three embryonic germ layers, the endoderm, ectoderm, and mesoderm, and are thus able to produce virtually all cell types. The ES cell capacity to generate various cell types has been studied extensively, and exploitation of ES cell characteristics allowed the production of several differentiated cell types of multiple tissues. Moreover, the process of ES cell differentiation provides a unique opportunity to observe early embryonic developmental events that are unattainable in the embryo itself. This chapter addresses the in vitro differentiation procedure of endothelial and vascular smooth muscle cells from human ES cells, with reference to similar studies performed in mouse and nonhuman primate ES cells, and provides several tools for the detailed characterization of differentiated cells.
Subject(s)
Cell Differentiation/physiology , Embryonic Stem Cells/cytology , Endothelium, Vascular/cytology , Muscle, Smooth, Vascular/cytology , Animals , Blastocyst/cytology , Cell Culture Techniques/methods , Cell Division , Collagen , Embryonic Development , Endothelium, Vascular/physiology , Humans , Mesoderm/cytology , Mesoderm/physiology , Mice , Muscle, Smooth, Vascular/physiologyABSTRACT
Embryonic stem cells, derived from the inner cell mass of embryos in the blastocyst stage, are cells capable of perpetual self-renewal and long-term propagation and hold the potential to differentiate to progeny of the three embryonic germ layers. Since their derivation approximately two decades ago, exploration of mouse ES cells made major advances in ES cell differentiation research and in the successful development and propagation of various cell types. The subsequent derivation of ES cells from human embryos allows detailed study of early developmental events practically unreachable in early human embryos, and the potential derivation of a variety of adult cell types differentiated from the ES cells holds immense therapeutic promise. Recently, the study of ES cell-derived teratomas identified the partial presence of human ES cell-derived premature vessels within the teratoma, and a preliminary protocol for the in vitro derivation of a vascular progenitor was developed based on the study with the mouse ES cells. Furthermore, genetic profiling identified a pattern of expression of various endothelial and vascular smooth muscle cell genes that provide additional information on the degree of vascular development that ES cells undergo. Finally, the clinical application of ES cells in transplantation medicine is closer than ever following the affirmation that human ES cell-derived endothelial progenitors conferred increased neovascularization in transplanted engineered skeletal muscle. This review summarizes these recent advances in vascular development from human ES cells and their potential clinical applications.
Subject(s)
Endothelium, Vascular/embryology , Muscle, Smooth, Vascular/embryology , Neovascularization, Physiologic/physiology , Stem Cell Transplantation , Stem Cells/cytology , Animals , Humans , Vascular Diseases/therapyABSTRACT
We carried out in vitro selection experiments to systematically probe the effects of TATA-box flanking sequences on its interaction with the TATA-box binding protein (TBP). This study validates our previous hypothesis that the effect of the flanking sequences on TBP/TATA-box interactions is much more significant when the TATA box has a context-dependent DNA structure. Several interesting observations, with implications for protein-DNA interactions in general, came out of this study. (i) Selected sequences are selection-method specific and TATA-box dependent. (ii) The variability in binding stability as a function of the flanking sequences for (T-A)4 boxes is as large as the variability in binding stability as a function of the core TATA box itself. Thus, for (T-A)4 boxes the flanking sequences completely dominate and determine the binding interaction. (iii) Binding stabilities of all but one of the individual selected sequences of the (T-A)4 form is significantly higher than that of their mononucleotide-based consensus sequence. (iv) Even though the (T-A)4 sequence is symmetric the flanking sequence pattern is asymmetric. We propose that the plasticity of (T-A)n sequences increases the number of conformationally distinct TATA boxes without the need to extent the TBP contact region beyond the eight-base-pair long TATA box.